Digitization stages

Every digitized object goes through a pipeline of four stages. Each stage builds on the previous ones, and the metadata is cumulative: a dcho folder contains triples from raw, rawp, and dcho steps.

Stages

raw

The original acquisition output. For photogrammetry-based objects, this means the photographs (PNG, JPG, TIF, NEF, RAW, ARW, CR2, RW2). For scanner-based objects, this is either .scan files or an Artec project (.a3d file with its data/ directory).

Processing step: 00

rawp

The processed raw model. This is the first 3D output after the initial processing of raw data: an OBJ or FBX file, sometimes accompanied by a diffuse texture (PNG/JPG).

Export components:

• OBJ: .obj + .mtl (material definitions)
• FBX: standalone

Processing steps: 00, 01

dcho

The Digital Cultural Heritage Object. This is the refined 3D model after geometry corrections, with a full set of PBR textures:

• Diffuse map (map_Kd in MTL files)
• Normal map (map_Bump)
• Roughness map (map_Ns)
• Metalness map (map_Pm)

Models can be multi-texture, meaning they may include multiple diffuse maps and additional PBR maps.

Processing steps: 00, 01, 02

dchoo

The optimized version for web-based real-time rendering. Exported as glTF (.gltf + .bin) with associated textures. The glTF file links textures through a three-level indirection: images[] (file references), textures[] (image bindings), and materials[] (role assignment: baseColorTexture, normalTexture, metallicRoughnessTexture).

This is the version served to online 3D viewers.

Processing steps: 00, 01, 02, 03, 04, 05, 06

Stage dependencies

raw  (step 00)
 |
 v
rawp (steps 00-01)
 |
 v
dcho (steps 00-02)
 |
 v
dchoo (steps 00-06)

Because metadata is cumulative, the author list grows at each stage. The people who created the dchoo include everyone from raw, rawp, and dcho as well.